Safety issue on world’s first liquid hydrogen carrier fixed
07 February 2023
The Australian Transportation Safety Bureau (ATSB) has said that an electrical component failure on the world’s first liquid hydrogen (LH2) carrier which caused a brief flame discharge, has now been fixed. The Suiso Frontier was built as a prototype ship to assess the technical aspects of transporting LH2 by sea.
Image: ATSB
The failure of an incorrectly-fitted electrical solenoid valve led to the brief propagation of flame from the Suiso Frontier’s gas combustion unit’s vent stack, an Australian Transport Safety Bureau investigation found. The incident on the vessel happened on 25 January 2022 while it was docked at the Port of Hastings in Victoria, Australia. The 116-metre Suiso Frontier had departed for its maiden voyage from Kobe, Japan on 25 December 2021 with 55 tonnes of LH2, and was to load additional LH2 from the gas liquefaction facility at Hastings before returning to Kobe.
After LH2 had been loaded at Hastings on 24 January 2022, the ship was still berthed on the evening of January 25 when the gas control equipment malfunction occurred. A worker on board the ship observed a yellow gas flame briefly propagate from the gas combustion unit’s vent stack on the ship’s deck. There was no subsequent fire or explosion, and no injuries or damage were reported.
Despite the malfunction, the test journey still went ahead and the ship’s builder Kawasaki Heavy Industries said the voyage showed that the shipping of LH2 was technically feasible.
An ATSB investigation found the gas combustion unit’s air fan discharge damper actuators – which regulate the flow of air into the unit – were fitted with direct current (DC) electrical solenoid valves, which were incompatible with the 230 V alternating current (AC) supply from the GCU control system.
“During roughly 400 hours of service prior to the occurrence, the solenoid valves were subjected to conditions for which they were not designed,” ATSB Chief Commissioner Angus Mitchell said. “When one of these solenoid valves failed, the fan discharge damper it was operating closed. Consequently, the temperature of the gas combustion unit increased, eventually resulting in the discharge of flame from the unit’s vent stack.”
In addition to the incorrect solenoid valve being fitted, the ATSB found the gas combustion unit was not equipped to detect the failure of the valve, nor the subsequent closing of the damper.
“Automated safety controls intended to detect a malfunction to prevent such an incident were not effective,” Mitchell added.
In response to the incident, the manufacturer of the gas combustion unit, Saacke, fitted limit switches on each air fan discharge damper to monitor damper position. In addition, the system’s control logic has been programmed to stop the unit if a fault is detected.
“The ATSB’s investigation highlights the importance of ensuring automated shipboard operating systems are equipped with safety controls to prevent hazardous consequences in the event of a malfunction,” Mitchell said. “The incident also shows the importance of stringent manufacturer quality controls to ensure correct system components are specified and fitted to equipment.”
Kawasaki Heavy Industries said in a statement that the ATSB’s investigation would help its approach and maintain safer operations in the future. The company added that there would be no impact on future construction plans for LH2 carriers.
Read the ATSB’s report in full by clicking here.
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